A freezer failure at the world's largest repository of human brains has led to the loss of 147 of them, including a rare collection of 53 brains from donors with autism. Researchers at the Harvard Brain Tissue Resource Center at McLean Hospital in Belmont, Massachusetts, only noticed the thaw – on 31 May – when they opened the freezer door; the temperature display still read -79 °C. The rising temperature had also failed to trigger two alarm systems on separate circuits.